Introduction

Apart from the Earth, the Moon is the only extraterrestrial body from which we have obtained samples from known locations. All accomplishments of the Apollo Program have provided unique ground truths and fundamental experimental standards for future explorations (e.g., Clementine, Lunar Prospector, SMART-1, SELENE, Chandrayaan-1, Lunar Reconnaissance Orbiter, and more in the future) and invaluable information for understanding the lunar origin and evolution represented in the following areas: (1) detailed geologic investigations to provide a known geologic context for all samples and experiments relating to the lunar surface, (2) physical and chemical analysis of lunar samples for use as standards for calibrating remote sensing observations and extrapolating their results to unsampled regions, (3) absolute dating of the samples to set references for lunar chronology, (4) experimental operations on the lunar surface and in orbit to provide data sets on the interior...